[Haskell-cafe] Monad Syntax

Henning Thielemann lemming at henning-thielemann.de
Mon Dec 13 22:30:23 CET 2010


On Mon, 13 Dec 2010, caseyh at istar.ca wrote:

> do
>   let x = 7
>   y <- x+1, Writer ("inc\n")
>   z <- 2*y, Writer ("double\n")
>   z-1, Writer ("dec\n")
>
> Or some other delimiter than the comma?


You can simply define your own syntax using an infix operator, say:

a # str = Writer (a, str)

do
   let x = 7
   y <- x+1 # "inc\n"
   z <- 2*y # "double\n"
   z-1 # "dec\n"




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